1. Field of the Invention
The present invention relates to an outer rotor superconductor journal bearing, and more particularly, to an outer rotor superconductor journal bearing capable of cooling a superconductor that is mechanically fixed to a module below a critical temperature.
2. Description of the Related Art
Generally, it is important that a journal bearing used for a rotation device can minimize a contact friction, reduce an energy loss, and bear a heavy load of solid of revolution caused by gravity or the like.
To meet the above requirement, a non-contact journal bearing has been developed. The non-contact journal bearing, which is a substitution of a contact bearing such as a ball bearing or a fluid journal bearing for fixing solid of rotation by contacting, floats the solid of revolution, and achieves revolution without a friction using an attractive force and repulsive force of a permanent magnet or electromagnet. However, the non-contact journal bearing needs an additional active control device for fixing an axis, which causes complexity of and increases costs.
Recently, owing to the development of a superconductor, a non-contact superconductor journal bearing for fixing the solid of revolution with respect to an axis direction and a radius direction without an additional active control by using properties of strongly repulsing a magnetic flux of the superconductor and fixing the injected magnetic flux has been developed.
In such an inner rotor superconductor journal bearing, a magnet ring of the rotor and the superconductor of a stator are spaced apart from each other by a predetermined gap due to a reinforcing member used to reinforce a magnet in an external circumference of the rotor, which deteriorates a floating capability. Furthermore, the superconductor is fixed inside a cryostat in order to cool the superconductor, which increases the space between the magnet ring of the rotor and the superconductor of the stator due to a wall of the cryostat.
Therefore, in order to minimize the space between the magnet ring of the rotor and the superconductor of the stator, an attempt is being made that an outer rotor superconductor journal bearing is used to remove the reinforcing member between the magnet ring of the rotor and the superconductor of the stator, move the superconductor outside the cryostat, cool the superconductor by conductive cooling, and enhance a magnetic fixing force of the bearing.
However, when the superconductor is permanently fixed to the cryostat during a process of manufacturing the conventional outer rotor superconductor journal bearing, the superconductor is damaged due to a different thermal expansion, the outer rotor superconductor journal bearing is in a large scale, causing difficulties when assembled and dissembled, and the permanently fixed superconductor makes it impossible to partially repair and replace the bearing.